Field of the Invention
The present invention relates to a planar coil element and a method for producing the planar coil element.
Related Background Art
Surface mount-type planar coil elements are conventionally used in various electrical products such as household devices and industrial devices. In particular, small portable devices have come to be required to obtain two or more voltages from a single power source to drive individual devices due to enhanced functions. Therefore, surface mount-type planar coil elements are used also as power sources to satisfy such a requirement.
One of such planar coil elements is disclosed in, for example, Japanese Patent Application Laid-Open (JP-A) No. 2009-9985. The planar coil element disclosed in this document includes an air core coil formed in a spiral shape in a plane and a magnetic sheet stacked on the air core coil and containing an oblate or needle-like soft magnetic metal powder dispersed in a resin material.
The air core coil may be covered with a resin paste containing an oblate or needle-like soft magnetic metal powder dispersed therein. However, when the soft magnetic metal powder has an oblate or needle-like shape, the resin paste has high viscosity. Such a high viscosity resin paste is very difficult to handle in some sort of production process such as printing.